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Hermetically tight design
Ideal technology for high-pressure homogenization

High-pressure homogenizers consist of both a pump acting as a pressure generator and a hydraulic consumer, which is called the homogenization valve. Picture: Lewa
High-pressure homogenizers consist of both a pump acting as a pressure generator and a hydraulic consumer, which is called the homogenization valve. (Picture: Lewa)

Short-term thermal treatment is used in the food industry for a wide range of products such as milk, mixed drinks or liquid foods. This treatment kills off any pathogenic micro-organisms and extends the shelf life of the products. Since high-pressure homogenization may not re-contaminate food products after thermal treatment, it must be ensured that all components being used have a hygienic or – even better – aseptic design, material selection and integration. To date, packed plunger pumps have primarily been relied upon as the type of pump technology installed in these applications. However, in terms of aseptic production safety, using these pumps is only the second-best choice. This is because, despite a design that accounts for plunger packing components with sterile barriers and flushing systems, there is a risk of recontamination after in-process CIP/SIP cleaning. Furthermore, the thermal load created here results in increased wear on the plunger and its sealing system. The consequence is a significantly reduced service life, especially when the food product being treated contains abrasive ingredients. One alternative is to use process diaphragm pumps. They feature a hermetically tight liquid end, which is hermetically separated from the hydraulic chamber and process environment by a diaphragm. This prevents the inside of the fluid chamber from becoming contaminated, ruling out any contamination of the process space—including the food product.

Listeria in cheese, E. Coli bacteria in meat and salmonella in baby formula—food scandals and recall campaigns by major manufacturers have become all too frequent in recent times, damaging the reputations of the manufacturers responsible. This phenomenon has been increasing customer awareness and putting more pressure on the industry. Especially for sensitive products and products with high hygienic standards, it is absolutely imperative to ensure hygienic production through flawless hygienic process steps, as this guarantees microbiological integrity. In doing so, the following points must be kept in mind: Safe and reliable aseptic manufacturing processes are necessary in achieving high microbiological quality and lasting stability while still meeting the customers’ high expectations for aspects such as high taste quality , healthiness and sustainability of the product. Short-term thermal treatment (UHT processes) and consistent downstream aseptic technology present a possible solution to this problem using reliable food-processing technology.

New trends in the food and beverage sector such as unprocessed and innovative ready-to-eat products pose certain challenges to the food industry supply chain with regard to food safety. This applies to both increasing expectations for freshness and the additives and preservatives put into food, which make it necessary to invest in different technologies than those used in previous production processes. The production chain is further affected by crossover-products between the food and pharmaceutical sectors such as ready-to-drink “nutritional beverages,” as they are called, which sometimes contain high proportions of abrasive solids (e.g. due to calcium and nuts) or ingredients with microbiological sensitivity. In producing such crossover products, empirical knowledge from the pharmaceutical GMP environment is advantageous. Here, nutritional supplements with functional milk protein sources, fruits and flavors are combined to form new beverages, which may require special attention during production depending on their acidity and pH values. These high requirements must be adhered to specifically when formulating baby foods and high-calorie clinical nutrition (liquid enteral/parenteral foods). During processing, there are key tasks that must be handled by the pump technology specifically, e.g. for feeding raw materials and creating formulations that match the recipe, including metering and mixing ingredients at the correct proportions. Since the end products are ideally stored at room temperature and are supposed to last for an extended time in shelf, short-term thermal treatment is recommended here as well. It is the optimal technology for killing off foreign germs at a high rate and should be followed by aseptic high-pressure homogenization using diaphragm pump technology. This prevents re-contamination and ensures gentle product treatment.

Freedom from residue and microbial safety in high-pressure homogenization

High-pressure homogenization is an application field that poses particular challenges to pump technology. The systems used in this field consist of a high-pressure pump used as a pressure generator in addition to a hydraulic consumer, which is called the homogenization valve. The purpose of the pump is to generate the energy for dispersion in the valve, to convey the fluid being dispersed and to ensure the exact flow rate in the process.

Working principles of high-pressure pumps for homogenization applications

The reciprocating high-pressure pumps that the high-pressure homogenization machines are equipped with are necessary for pumping the fluid from the suction side through a feed pump (usually a centrifugal pump) by increasing pressure on the homogenization unit (single-stage or two-stage valve). Homogenizer pumps are equipped with three to six pump heads. Process diaphragm pumps stand out for their robust mono-block design and because of the integrated worm gear with high hydraulic output thanks to very smooth running. Fluid valves with application-specific designs that have been optimized for wear and hygiene ensure reliable pumping on both the intake and discharge sides of the pump. Automated homogenization valves are controlled pneumatically and hydraulically. The droplet size during homogenization is determined mainly by the cavitation in the chamber of the second stage and is dependent on the pressure-drop there. Assuming incompressible fluids are handled, the flow rate of a reciprocating diaphragm process pump is reduced by a small amount as pressure increases and can be treated as a nearly constant value. Pressure fluctuations between a reciprocating pump and the homogenizer valve can be countered using pulsation-smoothing measures. This includes selecting suitable operating points for the pump and damping measures on the piping. Here, very specific dynamic simulation programs carried out within the scope of a pulsation analysis can provide support in the design.

For homogenization tasks following UHT treatment, the homogenization pump and the homogenization valve must consistently meet aseptic requirements so that the integrity of the products being treated remains ensured. However, many pumps still in use today are packed plunger pumps. For this type of unit, note that plunger packing components with sterile barriers and flushing systems must be incorporated into the design as a measure of preventing recontamination after in-process CIP/SIP cleaning. Moreover, contaminations caused by plunger abrasion in the packing area cannot be ruled out for this pump class. The preferable option for aseptic processes is thus to equip the homogenization steps with hermetically tight process diaphragm pumps.

Diaphragm pump technology eliminates fluid contamination

The diaphragm pump can be viewed as a successful evolution of the packed plunger pump. The diaphragm pump reaches an efficiency of up to 95 percent (in reference to what are called triplex diaphragm pumps, i.e. featuring three pump heads). The pump is set apart thanks to its low amount of wear and thanks to flow rates that are nearly independent of the discharge pressure. In homogenization applications, you benefit tremendously from the fact that diaphragm pumps are designed to operate without dynamic sealing systems. This guarantees a hermetically tight pump head, meaning zero emissions or substrate leaks from inside the system as well as zero ingress of germs from the outside. As a result, fluid contamination can be ruled out. This means that the diaphragm pump is the perfect solution for demanding applications. It is suitable for media that, for instance, have to be pumped with zero leaks and absolute operating reliability because they are hazardous or abrasive and must under no circumstances be released into the production environment, or media such as baby formula that have to remain sterile and free of contamination.

A hygienic or aseptic application requires additional special adjustments to the diaphragm pump head: A suitable pump head material such as stainless steel 1.4404 or, as an alternative, particularly corrosion-resistant austenitic materials such as 1.4439 or 1.4462 (Duplex), polished surfaces with an RA value < 0.8 µm and fluid chambers with minimal dead space and no gaps may make it possible to carry out CIP/SIP cleaning steps repeatedly and efficiently, thus ensuring sterile operation without dismantling. The design and installation of the pump should, however, allow for the cleaning results to be checked periodically while still minimizing the sterile interfaces in the pipe routing. Directives such as those of the European Hygienic Engineering Design Group (EHEDG) – specifically Document 17 (“Hygienic Design of Pumps, Homogenizers and Dampening Devices”) – or the 3-A Sanitary Standards 44-03 (“Sanitary Standards for Diaphragm Pumps”) and 04-05 (“Sanitary Standards for Homogenizers and Reciprocating Pumps”) provide information on how pumps for the food industry are to be designed and installed. Hygienic design aspects regarding cleaning and drainability of the pumps, valves and piping of sterile systems for the design of aseptic process connections of diaphragm pumps can also be found in the ASME BPE Standard in the version that is valid for the specific application.

Food & Beverage Plant Construction, Engineering & Components Videos

PolyOne
The single-screw extruder

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The single-screw extruder PolyOne Bühler

PolyOne is the latest innovation of Bühler Group for the aqua feed and pet food industry. A modular design, highest sanitation standards and excellent workmanship make it the ideal solution for specific needs.

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Conveying & Filling, Packaging, Labeling & Storage Food & Beverage News

New State-Of-The-Art Production
SIG announces further Asia-Pacific expansion

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As the Asia-Pacific region continues its appetite for aseptic carton packaging, SIG has announced investment in the region with the construction of a second production plant in Suzhou, China. (Picture: SIG)
As the Asia-Pacific region continues its appetite for aseptic carton packaging, SIG has announced investment in the region with the construction of a second production plant in Suzhou, China. (Picture: SIG)

As the Asia-Pacific region continues to be one of the major growth engines for aseptic carton packaging, SIG has announced investment in the region with the construction of a second production plant in Suzhou, China.

To meet current and future customer demand, the new 120,000 square meter plant is expected to be operational in early 2021 and will be situated at the Suzhou Industrial Park (SIP), close to the company’s existing production facility and Tech Centre. With a total investment of EUR 180 million, the new plant will ensure exceptional delivery on outstanding opportunities in the Asia-Pacific region, where most countries continue to grow significantly. The plant is expected to achieve world-class environmental, safety and operational performance right from the start.

The new production facility is testament to SIG’s strong partnership with SIP and the local government, as well as its unparalleled commitment to deliver world-class packaging, service and the most modern solutions to the rapidly growing Asian markets and to China in particular. SIG’s recently opened cutting-edge Tech Centre in Suzhou supports customer collaboration in the development and implementation of innovative product concepts and market-ready packaging solutions.

Across Asia, millions of people are only now starting to consume packaged food and beverages. The rise of new consumers, driven by increasing income, changing lifestyles and new consumption habits, represents a huge opportunity for aseptic carton packaging with its long shelf life without the need of a cooling chain.

At the same time, young and growing populations are adopting modern lifestyles in urban areas, with more on-the-go consumption, an increasing awareness of health and wellness, and a growing demand for high-quality nutritional food and beverage products.

“The food and beverage market in Asia has seen continuous growth and is expected to continue on that path. Our new production plant will ensure we continue to excel at bringing new and exciting product and packaging concepts to market, quickly and efficiently. Together with our Tech Centre close by, the new plant is another pivotal moment for SIG in Asia. We will grow our business in the APAC region, but also expedite true beverage and dairy innovation for our customers, so they can quickly adapt to the changing lifestyle needs of Asian consumers.”

Rolf Stangl, CEO at SIG

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Conveying & Filling, Packaging, Labeling & Storage Food & Beverage Plant Construction, Engineering & Components

Biodegradable products
Sustainable compounding

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Complete lab-scale system for Asahel Benin Sarl., consisting of a ZSK 26 Mc18 twin screw extruder, four feeders from Coperion K-Tron, as well as a water bath, air wipe and SP 50 strand pelletizer from Coperion Pelletizing Technology. (Picture: Coperion)
Complete lab-scale system for Asahel Benin Sarl., consisting of a ZSK 26 Mc18 twin screw extruder, four feeders from Coperion K-Tron, as well as a water bath, air wipe and SP 50 strand pelletizer from Coperion Pelletizing Technology. (Picture: Coperion)

Coperion has enabled Benin-based blown film manufacturer Asahel Benin Sarl. to produce sustainable, bio-based plastic films in the future by delivering a complete compounding system and sharing the corresponding process engineering expertise. The system includes a ZSK 26 Mc18 twin screw extruder, four highly accurate feeders from Coperion K-Tron, as well as a water bath, an air wipe and a strand pelletizer from Coperion Pelletizing Technology. Before plastic bags and packaging were banned in Benin in July of 2018, this west African manufacturer had made its plastic films using polyethylene (PE). The new law forced the company to completely convert its production. Following a successful test and training phase at Coperion’s Stuttgart test lab, Asahel Benin Sarl. will produce biodegradable compounds in its home country with the aid of the ZSK twin screw extruder, and will then further process these on its existing blown film machinery into biodegradable bags and packaging materials.

Importation, production, sale, and possession of petroleum-based plastic bags and packaging has been forbidden in Benin since 2018. Until then, Asahel Benin Sarl. had used both new PE compounds as well as recyclate for manufacturing its films that were then used predominantly in household products and in shopping bags for supermarkets.

Intensive tests at Stuttgart test lab

When the new law took effect, the blown film manufacturer had to radically alter its production. Asahel Benin Sarl. turned to the compounding experts at Coperion. From this first contact, a cooperative partnership quickly arose, as did a new corporate strategy thereafter. Asahel Benin Sarl. ordered a laboratory-scale compounding system to develop a biologically degradable compound formulation that could be used in existing blown film manufacturing facilities. The lab-scale system includes a ZSK 26 Mc18 twin screw extruder, four highly accurate powder, pellet, and liquid feeders, as well as a water bath, an air wipe and a strand pelletizer type SP 50. Before the complete system could be delivered to Benin and put into service, it was assembled and tested intensively at Coperion’s Stuttgart location in the test lab.

Sharing process engineering expertise

Throughout the entire project, Asahel Benin Sarl. could fall back on Coperion’s comprehensive, process engineering expertise, for both the mastery of the entire system’s complexity as well of as the seamless interaction of its components, and in particular relating to the twin screw extruder’s configuration. Formulations with starch content, for example, represent a particular challenge for configuring the twin screws, as the melting zone in the extrusion process must both melt polymers and plastify non-meltable starch while adding liquid. Moreover, David Romaric Tinkou, Development Leader of Asahel Benin Sarl., received comprehensive training on the compounding machine’s operation. Thus began the development of a formulation for the necessary biopolymer.

Flexible set up

Coperion’s experts designed the compounding system for Asahel Benin Sarl. very flexibly in order to enable maximum freedom in developing a suitable formulation. In so doing, the system can allow materials to be added from many different components as well as intensive melt devolatilization. Following the die head with nozzle comes a water bath for strand cooling, dewatering of the strand surfaces using an air wipe, and a strand pelletizer.

David Romaric Tinkou is very satisfied with how the project went: “It was clear quite quickly that we needed a new business strategy to keep operating our blown film plants here in Benin. I’m very happy that with Coperion, I encountered experienced experts in the field of biodegradable compounds. Coperion delivered not only the necessary technology, but also shared the necessary process engineering expertise with me so that we can manufacture biodegradable compounds ourselves now in Benin.”

Peter von Hoffmann, General Manager Business Unit Engineering Plastics & Special Applications at Coperion, explained: “We’re thrilled that we could support Asahel Benin Sarl. in switching over their production in order to accomplish it more sustainably. Biodegradable compounds from renewable raw materials unite high production-technical demands with environmental sustainability. Particularly for manufacturers of short-lived household, industrial and agricultural products, these compounds represent a long-term, sustainable alternative to petroleum-based raw materials such as PE. Typical areas of application include single-use flatware, trash bags and trash can liners, food packaging, shopping bags, drinking straws, and agricultural films.”

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